Process of producing material for purifying liquids



Patented Aug. 22, 1939 I 2,170,601

UNITED STATES PATENT OFFICE PROCESS OF PRODUCING mm I03 PURIFYING LIQUIDS No Drawing. Application January i, 1987, Serial No. 119,083

6 Claims. (Cl. 21l--205) 'nie present invention relatesto clarifying masuitably porous in character, and preferably a terial, and particularly to material suitable for phosphate is used to obtain the revivifying and clarifying, decolorizing andpurifying liquids, and hardening effect of nascent phosphoric acid the process of producing such material, preferupon the phosphatic particles as the salt is deably in the form of hard, durable granules. composed. Monoor di-amrnonium phosphate One of the objects of the invention is to prohave been found to be suitable for the purpose, vide a material having the general filtering, aband it also has been found that the addition of sorbing and purifying properties of bone black a small amount of a fluorine compound renders but to an enhanced degree, and having approxithe granules materially harder and more re- 10 mately the chemical composition of bone black. sistant to shock. 10 It further object of the invention is to produce In carrying, out the invention, the finely dia material of this kind utilizing "spent bone vided phosphatic material is mixed with the black", or the fines resulting from the production starch, glue, molasses or other binding agent. of virgin black", or other phosphatic mate- Should the phosphatic base be devoid of. carrial. Still further objects are to provide such bonaceous matter, or have less than the amount 18 mat rial in th m of ul s w h a e moi carbon desired, this is added in the form of r lls ye fli i ly r and rfl l to W thorganic material of animal, vegetable or mineral stand the handling incident to shipment and origin, preferably in the form of sawdust, or as well as the repeated heating and washing bituminous coal, or both. It is preferable that m by which such material is cleaned and reviviflcd these materials be mixed thoroughly, and to the 20 for use in some industries. Still further objects mixture there is added a solution of an ammoof the invention will be apparent from considernlum salt, preferably monoor di-ammonium ation of the following specification. phosphate, the solvent being in such an amount In a general way the invention comprises mixthat the mixture will form a heavy paste.

"- ins a d io mi s a m bodies of a fi e y The pasty mixtureisthen dried, it being desiras d v ded D P O a a and 8 binding 8 able to extrude, or press, or otherwise form the which will hold the particles together but which pasty a s i to relatively thin strips or ribbons, a s up h t a d d p s salt. to facilitate the drying operation and to obtain such as amm nium p osph t which p n heata maximum percentage of the mass in the form 8 W111 pos into 88865 which render the of granules of the desired size. The hard, dry

, product porous and an acid, such as phosphoric product is then crushed and screened to the deacid, which will act upon the phosphatic partisired size, the fines being again wetted and incles to bind them together and activate them and corporated in'another mix. to harden the granules, thus compensating for The hard, dry, screened granules are then ina the decrease of the binding efiect of the binding troduced into a retort of any suitable type in :5 agent as it is charred. which they are gradually heated to a tempera- More specifically, the invention comprises the ture snmciently high to char the organic matter mixing with finely comrninuted spent bone black, and decompose the ammonium phosphate and or the fines rejected in preparing virgin black" form ammonia and phosphoric acid, such temwhich is used in considerable quantity in the oil perature being usually about 500 C. As the 40 and sugar industries, or precipitated calcium starch, or other organic binding material, is carphosphates,'or ground phosphate rock, or any bonized it gradually loses its binding effect in other similar finely divided particles of phosholding the particles of the granule together but, phatic material, an organic binding material and before the granules soften -or disintegrate, the

a a suitable salt, such as'ammonium phosphate. phosphoric acid, or other acid, resulting from an h s th m tu e t r h inding the decomposition of the salt, reacts with some agent and decompose the salt. Carbon may be of the tricalcium phosphate of the particles to added, in the form of coal or sawdust, or similar bind them together, and this binding effect is material, to obtain the desired content of carenhanced as the temperature is increased.

' bon in the final product. The binding material Moreover, the carbonizaticn of the starch, or should be one which chars upon heating and is other binding agent, and other organic matter preferably an organic compound such as starch, produces gases which, together with the evoluglue, sugar, molasses or the like. The salt should tion of gaseous ammonia, renders the granules be one which yields gas upon decomposition, in porous or cellular in structure, and the carbon order that the granules of the product may be contained therein will be found to be thoroughly 56 activated form.

While not essential, it has been found desirable in order to increase the hardness of the product, to add a small quantity of some fluorine compound which is acted upon by the phosphoric acid freed in the retorting of the product. This fluo= rine reacts with the other materiam to render the final product appreciably harder and more resistant to shock, and it is believed that this is because of the formation of artificial fluorapatite, C8.1cF62(PO4) c.

When the organic matter has been completely carbonized, the temperature is raised to from 50%? C. to 809 C. and the product thus formed is composed of black granular particles of sumcient hardness and porosity to act as a highly efiicient filtering medium for removing coloring tter, suspended particles and dissolved impurities from oils and other liquids which it is desired to purify.

The following formulae have been found to yield satisfactory products, and illustrate how various types of phosphatic materials may be used: J

Bone black duct Parts Bone black mesh) ch 10 Dry mix Sodium fluosilicate 3 Ammonium phosphate 10 water 80 Solution Precipitated tricalcium phosphate Parts Precipitated tricalcium phosphate -3 100' Bituminous coal 100 mesh 3 Sawdust (30 mesh) 7 Dry Starch 15 Sodium fluosilicate 3 Ammonium phosphate 12 Water 8S lsohmon Phosphate rock Parts Phosphate rock (2.00 mcsh)s 100 Bituminous coal 100 mesh 3 Sawdust (30 mesh) 7 Dry mm Starch 17. 5

Ammonium phosphate l7. 5 Water 40 While it can not be with certainty what the chemical reactions are, it is believed that the reactions generally are as follows:

When the mixture of materials, as above described, is first heated and the temperature gradually rises, the organic binder matter chars to form carbon, and the ammonium phosphate de composes to form ammonia and phosphoric acid, according to the equation:

Inasmuch as the bone black, phosphate rock, or similar materials, contain calcium carbonate, usually in an amount from 6% to 10%, the nascent phosphoric acid derived from the amphosphate immediately reacts with such calcium carbonate to form carbonic acid and tricalcium phosphate, according to the equation:

. calcium phosphate which acts as a binder to hold We particles together and prevent any breaking distributed throughout the granule m a highly up of the granules, and the binding properties of the tri-calcium phosphate are enhanced as the temperature is gradually increased.

The action of the fluorine compounds, such as for instance sodium flucsilicate, is as follows:

The sodium fluosilicate is decomposed by the heat to form sodium fluoride and sillcon-tetra fluoride, according to the equation:

The nascent phosphoric acid derived from the decomposition of the-ammonium phosphate then attacks the sodium fluoride to form sodium phosphate and hydrofluoric acid, in accordance with. the equation:

The hydrofluoric acid then attacks part'of the calcium carbonate present in the bone black, phosphate rock or similar material, to form. carbonic acid and calcium fluoride, in accordance with the equation:

As the temperature continues to rise the calcium fluoride combines with the trl-calcium phosphate to form what is believed to be artificial fiuorapatite, according to the equation:

The formation of the fluorapatite increases the hardness of the granules that constitute the final product.

It will be understood that the invention is not limited to the process herein described for eflecting the formation or the materials into granules, as various other methods may be used.

We do not wish to limit] this invention to the use of absolutely definite proportions of the several ingredients since thenature of the phos-- phatic material employed will necessitate varying the quantities of the other reagents employed. Also the physical properties and-chemical composition of the product may be altered, depending'upon the purpose for which the productis to be used. l v

It is evident, therefore, that the product is susceptible of very close control yet can be altered to meet the requirements of the consumer'without departing from the spirit of the invention.

The term filtering material is used herein to include material for clarifying, decoloring or puriiying liquids or gases, whether mixed with the fluid or used in a filter bed through which the fluid is passed, that is, to define a material for any of the uses for which bone blackand similar materialsare utilized. 1 1

What is claimed is:

1. A process of producing filtering material, comprising adding to finely divided phosphatic material containing as an essential ingredient a substantial amount of calcium, ,a carbohydrate binding material and ammonium phosphate, and

gradually heating the mass to a temperature suificiently high to char the'carbohydrate binding material and decompose the ammonium phosphate.

2. A process of forming a, granular filtering material, comprising mixing finely divided particles o1 phosphatic nfdterial containing as an essential ingredient a substantial amount of calcium, a carbohydrate binding material, and a solution of ammonium phosphate, converting the mass into granular form, and gradually heating the granules to aten'lperature. between 500 and 850 C.

3. A process of producing filtering material, comprising mixing fine particlesmt phosphatio material containing as an\, essential ingredient a substantial amount of calcium, a carbohydrate binding agent, and ammonium phosphate with suflicient water to form a paste, drying and crushing said paste to form granules, and gradually "heating said granules to carbonize the organic binder and decompose said ammonium phosphate.

4. A process of producing filtering material, comprising mixing bone black, a carbohydrate binding agent, and ammonium phosphate with sufiicient water to form a pasty mass, converting the mass into granules, and gradually heating the granules to a temperature sufllciently high to decompose the ammonium phosphate.

material containing as an essential ingredient a substantial amount of calcium, a carbohydrate binding agent, ammonium phosphate and a small amount of a decomposable fluorine compound, converting the mixture into granules, and heating the granules to carbonize the carbohydrate binding agent and decompose the fluorine compound and the ammonium phosphate.

6. A process of producing filtering material,

comprising mixing finely divided particles of 10 phosphatic material containing as an essential ingredient a substantial amount of calcium, a carbohydrate binding agent, an ammonium phosphate'and a small amount of a decomposable fluorine compound, converting said mixture into granules, and gradually heating said granules to a temperature between 500 C. and 850 C.

STANSBURY MJWILSON. WILLIAM H. WAGGAMAN. 

